Examples of conventionally known battery systems include one composed of a plurality of battery elements connected in parallel, each of which is composed of a plurality of battery cells connected in series (See, for example, Patent Document 1). A battery system disclosed in Patent Document 1 uses specific address information assigned to each of a plurality of battery elements for detecting the remaining battery capacity of each battery element. The battery system of Patent Document 1 enables highly accurate management of the remaining battery capacities of the plurality of battery elements.